Outliner showing duplicate entries for same object after python script parenting
bpy.ops.mesh.primitive_plane_add(location = tv.location, rotation = tv.rotation_euler)


creates the plane in the currently active collection (which seems to be the root here).

As an object can be in several collections, you'll need to unlink it from root or from its current collection:

newBar.users_collection[0].objects.unlink(newBar)


Then link it to the tv (first) collection:

tv.users_collection[0].objects.link(newBar)